<meta name=
"description" content=
"Pmw - a toolkit for building high-level compound widgets in Python">
<meta name=
"content" content=
"python, megawidget, mega widget, compound widget, gui, tkinter">
<title>Pmw.MegaArchetype reference manual
</title>
<body bgcolor=
"#ffffff" text=
"#000000" link=
"#0000ee"
vlink=
"551a8b" alink=
"ff0000">
<h1 ALIGN=
"CENTER">Pmw.MegaArchetype
</h1>
<dt> <h3>Name
</h3></dt><dd>
abstract base class for all Pmw megawidgets
<dt> <h3>Description
</h3></dt><dd>
This class is the basis for all Pmw megawidgets. It provides
methods to manage options and component widgets.
</p><p> This class is normally used as a base class for other classes. If
the
<em>hullClass
</em> argument is specified, such as in the
<a href=
"MegaWidget.html">Pmw.MegaWidget
</a> and
<a href=
"MegaToplevel.html">Pmw.MegaToplevel
</a> classes, a container widget is created to act
as the parent of all other component widgets. Classes derived
from these sub classes create other component widgets and options
to implement megawidgets that can be used in applications.
</p><p> If no
<em>hullClass
</em> argument is given to the constructor, no
container widget is created and only the option configuration
functionality is available.
</p><dt> <h3>Components
</h3></dt><dd>
A megawidget is generally made up of other widgets packed
within the megawidget's containing widget. These sub-widgets
are called the
<em>components
</em> of the megawidget and are given
logical names for easy reference. The component mechanism
allows the user of a megawidget to gain controlled access to
some of the internals of the megawidget, for example to call a
method of a component or to set a component's configuration
<p> <strong>Sub components:
</strong> If a component is itself a megawidget containing
sub-components, then these sub-components can be referred to
using the notation
<em>component_subcomponent
</em>. For example,
<a href=
"ComboBox.html">Pmw.ComboBox
</a> has a component named
<strong>entryfield
</strong> which is an
instance of
<a href=
"EntryField.html">Pmw.EntryField
</a>, which itself has a Tkinter.Entry
component named
<strong>entry
</strong>. In the context of the combobox, this
entry widget can be referred to as
<strong>entryfield_entry
</strong>.
</p><p> <strong>Component aliases:
</strong> Because the sub-component notation may
make component names inconveniently long, components and
sub-components can be aliased to simpler names. For example,
the
<strong>entryfield_entry
</strong> sub-component of
<a href=
"ComboBox.html">Pmw.ComboBox
</a> is aliased
to simply
<strong>entry
</strong>. If there is no conflict in component
names, sub-component names are usually aliased to the name of
the
"leaf" component.
</p><p> <strong>Component groups:
</strong> Similar components of a megawidget can be
given a
<em>group
</em> name, which allows all components of a group
to be referenced using the one group name. For example, the
two arrow components of
<a href=
"Counter.html">Pmw.Counter
</a> have a group name of
<strong>Arrow
</strong>.
Also, megawidgets that can create an unlimited number of
similar components, such as
<a href=
"ButtonBox.html">Pmw.ButtonBox
</a>, create each of these
components with the same group name. By convention, group
names begin with a capital letter.
</p><dt> <h3>Options
</h3></dt><dd>
A megawidget defines options which allow the megawidget user
to modify the appearance and behaviour of the megawidget.
Using the same technique as Tkinter widgets, the values of
megawidget options may be set in calls to the constructor and
to
<code>configure()
</code> and the values may be queried by calls to
<code>cget()
</code> and
<code>configure()
</code>. Like Tkinter widgets, megawidget
options are initialised with default values. Also, if the
<em>useTkOptionDb
</em> option to
<code>Pmw.initialise()
</code> has been set,
then the Tk option database will be queried to get the initial
values. Strings found in the option database are converted
to python objects (integer, float, tuple, dictionary, etc)
using a restricted
<code>eval()
</code> call. Anything that is not accepted by
<code>eval()
</code> is treated as a string.
</p>
<p> <strong>Inherited options:
</strong> As well as the options defined in a class,
a derived class inherits all options of its base classes. The
default value of an option defined by a base class may be
modified by the derived class.
</p><p> <strong>Initialisation options:
</strong> Some megawidget options can only be
set in the call to the constructor. These are called
<em>initialisation options
</em>. Unlike normal configuration
options, they cannot be set by calling the
<code>configure()
</code><p> <strong>Component options:
</strong> Options of the components of a megawidget
can be referred to using the notation
<em>component_option
</em>.
Like the megawidget options, component options can be used in
calls to the constructor and to the
<code>cget()
</code> and
<code>configure()
</code> methods. For example, the
<strong>state
</strong> option of the Tkinter.Text
<strong>text
</strong> component of
<a href=
"ScrolledText.html">Pmw.ScrolledText
</a> may be set by calling
</p>
<dl><dd><pre> widget.configure(text_state = 'disabled')
</pre></dd></dl>
<p> Sub-components, component aliases and component groups may
also be combined with options. For example, the
<strong>state
</strong> option of the
<strong>entryfield_entry
</strong> component of
<a href=
"ComboBox.html">Pmw.ComboBox
</a> may be set by calling
</p><dl><dd><pre> combobox.configure(entryfield_entry_state = 'normal')
</pre></dd></dl>
<p> Since it has an alias, it is more convenient to use the
<dl><dd><pre> combobox.configure(entry_state = 'normal')
</pre></dd></dl>
<p> Also, the background color of both arrows of
<a href=
"Counter.html">Pmw.Counter
</a>
can be set using the
<strong>Arrow
</strong> component group.
</p><dl><dd><pre> counter.configure(Arrow_background = 'aliceblue')
</pre></dd></dl>
<dt> <h3>The pyclass component option
</h3></dt><dd>
The
<strong>pyclass
</strong> component option is a special notation that can
be used to specify a non-default python class for a component.
This can only be used when the component is being constructed.
For a component created during the construction of its parent
megawidget, this option must be given to the constructor in
the form
<em>component_pyclass
</em>. For example, to change the
python class of the
<strong>text
</strong> sub-component of
<a href=
"TextDialog.html">Pmw.TextDialog
</a> to a class
<strong>FontText.Text
</strong></p><dl><dd><pre> dialog = Pmw.TextDialog(text_pyclass = FontText.Text)
</pre></dd></dl>
<p> For components created after the construction of the parent
megawidget, the
<strong>pyclass
</strong> option must be passed into the
method which constructs the component. For example, to set
the python class of a button in
<a href=
"ButtonBox.html">Pmw.ButtonBox
</a> to a class
<strong>MyButton
</strong>:
</p>
<dl><dd><pre> buttonBox.add('special', pyclass = MyButton)
</pre></dd></dl>
<p> The new python class of the component must support all methods
and options that are used by the megawidget when operating on
the component. The exact interface required for each
component is not documented. You will have to examine the Pmw
source code. However, any class derived from the default
class of a component can be used as the new class of the
component, as long as all of the original methods and options
are still supported. For example, any class derived from
<strong>Tkinter.Text
</strong> can be used as the class of the
<strong>text
</strong>
sub-component of
<a href=
"TextDialog.html">Pmw.TextDialog
</a>.
</p><p> The
<strong>pyclass
</strong> component option should not be confused with the
<strong>class
</strong> option that some of the Tk widgets support. The
<strong>class
</strong> option sets the Tk option database class for the
widget and is used by Tk to query the database for the default
values of the widget's other options. The name
<strong>pyclass
</strong> was
chosen so that it did not conflict with any known Tk options.
</p><dt> <h3>Construction
</h3></dt><dd>
The constructors of classes derived from this class all accept
the same arguments: one positional argument and any number of
keyword arguments. The positional argument defaults to
<strong>None
</strong> (meaning the root window) and specifies the widget to use as
the parent when creating the
megawidget's
<strong>hull
</strong> component. The keyword arguments define
initial values for options. The format for the constructors
of derived classes is:
</p><dl><dd><pre> def __init__(self, parent = None, **kw):
</pre></dd></dl>
<dt> <h3>Methods
</h3></dt><dd>
<a name=method.addoptions
></a>
<dl><dt> <strong>addoptions
</strong>(
<em>optionDefs
</em>)
</dt><dd>
Add additional options for this megawidget. The
<em>optionDefs
</em> argument is treated in the same way as for the
<code>defineoptions()
</code><p> This method is for use by derived classes. It is only used if a
megawidget should conditionally define some options, perhaps
depending on the value of other options. Usually, megawidgets
unconditionally define all their options in the call to
<code>defineoptions()
</code> and do not need to use
<code>addoptions()
</code>. This
method must be called after the call to
<code>defineoptions()
</code> and
before the call to
<code>initialiseoptions()
</code>.
</p><dl><dt> <strong>cget
</strong>(
<em>option
</em>)
</dt><dd>
Return the current value of
<em>option
</em> (which should be in the
format described in the
<strong>Options
</strong> section). This method is also
available using object subscripting, for example
<code>myWidget['font']
</code>. Unlike Tkinter's cget(), which always returns
a string, this method returns the same value and type as used when
the option was set (except where
<em>option
</em> is a component option
and the component is a Tkinter widget, in which case it returns
the string returned by Tcl/Tk).
</p><a name=method.component
></a>
<dl><dt> <strong>component
</strong>(
<em>name
</em>)
</dt><dd>
Return the component widget whose name is
<em>name
</em>. This
allows the user of a megawidget to access and configure component
<a name=method.componentaliases
></a>
<dl><dt> <strong>componentaliases
</strong>()
</dt><dd>
Return the list of aliases for components. Each item in the list
is a tuple whose first item is the name of the alias and whose
second item is the name of the component or sub-component it
<a name=method.componentgroup
></a>
<dl><dt> <strong>componentgroup
</strong>(
<em>name
</em>)
</dt><dd>
Return the group of the component whose name is
<em>name
</em> or
<strong>None
</strong> if it does not have a group.
</p><a name=method.components
></a>
<dl><dt> <strong>components
</strong>()
</dt><dd>
Return a sorted list of names of the components of this
<a name=method.configure
></a>
<dl><dt> <strong>configure
</strong>(
<em>option
</em> =
<strong>None
</strong>, **
<em>kw
</em>)
</dt><dd>
Query or configure the megawidget options.
</p><p> If no arguments are given, return a tuple consisting of all
megawidget options and values, each as a
5-element tuple
(
<em>name
</em>,
<em>resourceName
</em>,
<em>resourceClass
</em>,
<em>default
</em>,
<em>value
</em>).
This is in the same format as the value returned by the standard
Tkinter
<code>configure()
</code> method, except that the resource name is
always the same as the option name and the resource class is the
option name with the first letter capitalised.
</p><p> If one argument is given, return the
5 element tuple for
<em>option
</em>.
</p>
<p> Otherwise, set the configuration options specified by the keyword
arguments. Each key should be in the format described in the
<strong>Options
</strong> section.
</p>
<a name=method.createcomponent
></a>
<dl><dt> <strong>createcomponent
</strong>(
<em>componentName
</em>,
<em>componentAliases
</em>,
<em>componentGroup
</em>,
<em>widgetClass
</em>, *
<em>widgetArgs
</em>, **
<em>kw
</em>)
</dt><dd>
Create a component widget by calling
<em>widgetClass
</em> with the
arguments given by
<em>widgetArgs
</em> and any keyword arguments. The
<em>componentName
</em> argument is the name by which the component will
be known and must not contain the underscore,
<strong>'_'
</strong>, character.
The
<em>componentGroup
</em> argument specifies the group of the
component. The
<em>componentAliases
</em> argument is a sequence of
2-element tuples, whose first item is an alias name and whose
second item is the name of the component or sub-component it is to
<p> If this method is called during megawidget construction, any
component options supplied to the megawidget constructor which
refer to this component (by
<em>componentName
</em> or
<em>componentGroup
</em>)
are added to the
<em>kw
</em> dictionary before calling
<em>widgetClass
</em>. If
the dictionary contains a
<strong>'pyclass'
</strong> key, then this item is
removed from the dictionary and the value is used instead of
<em>widgetClass
</em>. For more details see
<strong>The pyclass component option
</strong>
<p> This method may be called by derived classes during or after
megawidget construction. It returns the instance of the class
<a name=method.createlabel
></a>
<dl><dt> <strong>createlabel
</strong>(
<em>parent
</em>,
<em>childCols
</em> =
<strong>1</strong>,
<em>childRows
</em> =
<strong>1</strong>)
</dt><dd>
Create a
<strong>Tkinter.Label
</strong> component named
<strong>'label'
</strong> in the
<em>parent
</em> widget. This is a convenience method used by several megawidgets
that require an optional label. The widget must have options
named
<strong>labelpos
</strong> and
<strong>labelmargin
</strong>. If
<strong>labelpos
</strong> is
<strong>None
</strong>, no
label is created. Otherwise, a label is created and positioned
according to the value of
<strong>labelpos
</strong> and
<strong>labelmargin
</strong>. The label
is added to the parent using the
<code>grid()
</code> method, with
<em>childCols
</em> and
<em>childRows
</em> indicating how many rows and columns the label
should span. Note that all other child widgets of the parent
<em>must
</em> be added to the parent using the
<code>grid()
</code> method. The
<code>createlabel()
</code> method may be called by derived classes during
megawidget construction.
</p><a name=method.defineoptions
></a>
<dl><dt> <strong>defineoptions
</strong>(
<em>keywords
</em>,
<em>optionDefs
</em>,
<em>dynamicGroups
</em> =
<strong>()
</strong>)
</dt><dd>
Create options for this megawidget. The
<em>optionDefs
</em> argument
defines the options. It is a sequence of
3-element tuples,
(
<em>name
</em>,
<em>default
</em>,
<em>callback
</em>), where
<em>name
</em> is the name of the
option,
<em>default
</em> is its default value and
<em>callback
</em> is the
function to call when the value of the option is set by a call to
<code>configure()
</code>. The
<em>keywords
</em> argument should be the keyword
arguments passed in to the constructor of the megawidget. The user
may override the default value of an option by supplying a keyword
argument to the constructor.
</p><p> If any option created by a base class is also defined by
<em>optionDefs
</em>, then the derived class's default value will take
precedence over the base class's. If the
<em>callback
</em> field is not
<strong>None
</strong>, then this will also override the callback set by the base
<p> If
<em>callback
</em> is
<strong>Pmw.INITOPT
</strong>, then the option is an
<em>initialisation option
</em>.
</p>
<p> The
<em>dynamicGroups
</em> argument contains a list of the groups of the
components created dynamically by this megawidget. If a group is
included in this list, then it not an error if a keyword argument
for the group is given to the constructor or to
<code>configure()
</code>,
even when no components with this group have been created.
</p><p> If
<code>defineoptions()
</code> is called, it must be called once in the
megawidget constructor before the call to the constructor of the
base class and there must be a matching call to
<code>initialiseoptions()
</code> at the end of the constructor.
</p>
<a name=method.destroy
></a>
<dl><dt> <strong>destroy
</strong>()
</dt><dd>
Destroy the
<strong>hull
</strong> component widget, if it exists, including all
<a name=method.destroycomponent
></a>
<dl><dt> <strong>destroycomponent
</strong>(
<em>name
</em>)
</dt><dd>
Remove the megawidget component called
<em>name
</em>. This method may be
called by derived classes to destroy a megawidget component. It
destroys the component widget and then removes all record of the
component from the megawidget.
</p><a name=method.hulldestroyed
></a>
<dl><dt> <strong>hulldestroyed
</strong>()
</dt><dd>
Return true if the Tk widget corresponding to the
<strong>hull
</strong> component
<a name=method.initialiseoptions
></a>
<dl><dt> <strong>initialiseoptions
</strong>(
<em>dummy
</em> =
<strong>None
</strong>)
</dt><dd>
Check keyword arguments and call option callback functions. This
method must be called, at the end of a megawidget constructor, if
and only if
<code>defineoptions()
</code> was also called in the constructor.
The
<em>dummy
</em> argument is not required, but is retained for
backwards compatibility.
</p><p> It checks that all keyword arguments given to the constructor have
been used. If not, it raises an error indicating which arguments
were unused. A keyword is defined to be used if, during the
construction of a megawidget, it is defined in a call to
<code>defineoptions()
</code> or
<code>addoptions()
</code> (by the megawidget or one of
its base classes), or it references, by name, a component of the
megawidget, or it references, by group, at least one component.
It also calls the configuration callback function for all options
that have a callback.
</p><p> This method is only effective when called by the constructor of
the
<em>leaf
</em> class, that is, the class in the class hierarchy which
first called
<code>defineoptions()
</code>. For all other classes in the
class hierarchy (base classes), the method returns immediately.
</p><a name=method.interior
></a>
<dl><dt> <strong>interior
</strong>()
</dt><dd>
Return the widget framing the interior space in which any children
of this megawidget should be created. By default, this returns
the
<strong>hull
</strong> component widget, if one was created, or
<strong>None
</strong> otherwise. A subclass should use the widget returned by
<code>interior()
</code> as the parent of any components or sub-widgets it
creates. Megawidgets which can be further subclassed, such as
<a href=
"Dialog.html">Pmw.Dialog
</a>, should redefine this method to return the widget in
which subclasses should create children. The overall containing
widget is always available as the
<strong>hull
</strong> component.
</p><a name=method.isinitoption
></a>
<dl><dt> <strong>isinitoption
</strong>(
<em>option
</em>)
</dt><dd>
If
<em>option
</em> is an initialisation option, return true. Otherwise,
return false (the option is a configuration option). The
<em>option
</em> argument must be an option of this megawidget, not an option of a
component. Otherwise an exception is raised.
</p><a name=method.options
></a>
<dl><dt> <strong>options
</strong>()
</dt><dd>
Return a sorted list of this megawidget's options. Each item in
the list is a
3-element tuple, (
<em>option
</em>,
<em>default
</em>,
<em>isinit
</em>),
where
<em>option
</em> is the name of the option,
<em>default
</em> is its default
value and
<em>isinit
</em> is true if the option is an initialisation
<center><P ALIGN=
"CENTER">
<IMG SRC = blue_line.gif ALT =
"" WIDTH=
320 HEIGHT=
5>
<center><P ALIGN=
"CENTER">
-
<a href=
"index.html">Home
</a> <br>Manual page last reviewed:
22 May
1998
projects / OpenSPARC-T2-SAM / blob